Drainage foil for use in an installation for producing a paper web with a fabric belt, which can be moved over a multiplicity of drainage foils oriented transversely to its direction of movement

ABSTRACT

A drainage foil for use in an installation for producing a paper web with a fabric belt, which can be moved over a multiplicity of drainage foils oriented transversely to a direction of movement. A surface of the drainage foil is formed with a defined profiling, which has elevations and/or depressions. The vertical extent of the profiling is at least 0.1 mm.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority, under 35 U.S.C. § 119, of Austrianpatent application A 344/2017, filed Aug. 28, 2017; the priorapplication is herewith incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The actual invention further relates to a kit and an installation forproducing a paper web.

Known installations for producing a paper web have a closed loop fabricbelt which is kept circulating by transport rollers and onto which, atthe start of the installation, a fibrous stock is sprayed. In a firstregion of the installation, the fabric belt is moved over drainage foilsand over suction boxes formed with drainage foils, by which liquid thathas emerged from the fibrous stock is stripped off and sucked away. Infurther regions of the installation, the paper web produced on thefabric belt is dried by use of felt belts.

The drainage foils found in such an installation, which are orientedtransversely to the direction of movement of the fabric belt, are foilsproduced from metal or from plastic which, on their upper side whichfaces the fabric belt in the operating position, can be provided with anoverlay of a wear-resistant material, in particular of plane-groundceramic plates. The ceramic plates consist in particular of Al oxide, ofZr oxide, of Si nitride and of Si carbide. The fabric belt is moved overthe drainage foils at a speed of 1 m/s to 40 m/s. By means of thedrainage foils, first the fabric belt is supported. Second, the drainagefoils serve to strip off from the fabric belt liquid that has escapedfrom the fibrous stock and is found on the underside of the fabric belt.By means of an oblique position of a first group of drainage foils withrespect to the fabric belt, wedge-shaped interspaces can be in this caseformed between the surfaces of the drainage foils and the fabric belt,which interspaces enlarge in the direction of movement of the fabricbelt, which means that, because of the movement of the fabric belt, asuction action is exerted on the fibrous stock found on the latter, bymeans of which liquid found in the fibrous stock is sucked away.Underneath a second group of drainage foils there are suction boxes, bywhich a suction action is likewise exerted on the fibrous stock found onthe fabric belt. The liquid that has escaped from the fibrous stock as aresult is led away through the suction boxes.

During the movement of the fabric belt over the drainage foils, thefabric belt rests on the surfaces of the drainage foils or on theceramic plates found on the latter, as a result of which high frictionalresistances are caused, which have to be overcome by the transportrolls. In addition, as a result the surfaces of the drainage foils andthe fabric belt are subjected to high wear, for which reason thedrainage foils and the fabric belt have only short service lives.

SUMMARY OF THE INVENTION

The actual invention is based on the object of devising a drainage foilby means of which, during operation of such a fabric belt installation,the frictional resistances occurring between the fabric belt and theindividual drainage foils are reduced. According to the invention, thisobject is achieved in that the surface of the drainage foils is formedwith a defined profiling, which has elevations and/or depressions,wherein the vertical extent of the profiling is at least 0.1 mm. Withinthe scope of the invention, the elevations and the depressions can beimplemented and/or distributed randomly or in a non-concretely definedmanner. However, in the invention it is preferred if the elevations andthe depressions have a defined profiling and/or are distributed in adefined manner on the surface, since more specific influencing of thefriction is therefore possible. Preferably but not necessarily, thedrainage foil is formed on its surface assigned to the fabric belt inthe operating position with a multiplicity of ceramic plates locatedbeside one another which, on their surface, are formed with definedprofiling in the form of elevations and/or of depressions, wherein thevertical extent of the profiling is at least 0.1 mm.

According to a preferred embodiment of the invention, the verticalextent is up to 3 mm, preferably up to 2.5 mm or up to 1.6 mm, inparticular 0.2 mm up to 0.8 mm.

The surface of the drainage foil can be formed with profiling orientedin the longitudinal extent of the drainage foil or enclosing an acuteangle with the latter. The profiling preferably has the shape of ribsthat are triangular in cross section, rectangular foils or wave-likefoils, other profilings also being possible in the context of theinvention, however. Furthermore, the profilings of ceramic plateslocated beside one another can be offset with respect to one anotherboth in and also transversely to the longitudinal direction of thedrainage foil and/or different. In addition, the longitudinal extent ofthe elevations and/or the depressions can enclose an angle of 0° to 80°with the longitudinal direction of the drainage foil. Furthermore, theprofiling can be formed by depressions located at a distance from oneanother, in particular by cut-outs that are concave in cross section orcylindrical holes.

According to the invention, the surface of the drainage foils can alsohave a convex curvature in the section transverse to the longitudinalextent of the drainage foil, wherein, in the invention, it is preferredfor the curvature to have a radius of 100 mm to 500 mm, preferably of200 mm to 350 mm.

Finally, it is preferred in the invention if the side edges of thesurface of the drainage foil are rounded in cross section with a radiusof 0.5 mm to 5 mm, preferably of 1 mm to 3 mm.

In known drainage foils, the surfaces that face the fabric belt in theoperating position, which, in particular, are coated with ceramicplates, are plane-ground, having surface roughness values Ra of 0.15 μmto 0.7 μm. Because of the plane grinding of the surfaces of the ceramicplates and the low roughness values achieved hereby, according to theknown prior art the frictional resistances occurring between thesurfaces of the drainage foils, in particular the surfaces of theceramic plates, and the fabric belt moved over the latter should beminimized.

By contrast, the actual invention is based on the finding that, with asubstantially intensified profiling of the surfaces with definedelevations and depressions, bow waves occur in the liquid which islocated in the depressions as a result of the fabric belt moved over thedrainage foils, by which waves the fabric belt in the regions of theelevations is raised above the latter, there being a layer of liquidbetween the fabric belt and the elevations, by which the frictionalresistances occurring between the fabric belt and the elevations arereduced significantly.

Further preferred embodiments of the invention are the subject matter ofthe remaining sub claims.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin a drainage foil for use in an installation for producing a paper webwith a fabric belt, which can be moved over a multiplicity of drainagefoils oriented transversely to its direction of movement, it isnevertheless not intended to be limited to the details shown, sincevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a diagrammatic, sectional view of an installation forproducing a paper web with a fabric belt, which is moved over drainagefoils and a suction box located underneath, in a section located in thelongitudinal direction of the movement of the fabric belt;

FIG. 1A is an illustration of detail X from FIG. 1 on a scale highlyenlarged with respect to FIG. 1;

FIG. 2 is a perspective view of a first embodiment of a drainage foilaccording to the invention in an axonometric illustration;

FIG. 3 is a cross-sectional view of the drainage foil according to FIG.2 on a scale highly enlarged with respect to FIG. 2;

FIG. 3A is an illustration corresponding to FIG. 1A to explain a mode ofaction of the drainage foil according to FIG. 3, on a scale highlyenlarged with respect to FIG. 3;

FIGS. 4, 4A and 4B are cross-sectional views of three furtherembodiments of the drainage foil according to the invention;

FIG. 5 is a plan view of a further embodiment of a drainage foilaccording to the invention;

FIG. 5A is a cross-section view taken along the line V-V from FIG. 5;

FIG. 6 is a plan view of another embodiment of the drainage foilaccording to the invention;

FIG. 6A is a sectional view taken along the line VI-VI from FIG. 6;

FIG. 6B is a sectional view of yet another embodiment of the drainagefoil according to the invention;

FIG. 7 is a sectional view of the drainage foil according to theinvention according to FIG. 2 and on a scale enlarged with respect toFIG. 2;

FIG. 8 is a sectional view of a section of an installation for producinga paper web, formed with drainage foils according to the invention, witha fabric belt moved over the drainage foils and with a further formationof the surfaces of the drainage foils; and

FIG. 8A is a sectional view showing a detail Y from FIG. 8, on a scalehighly enlarged with respect to FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures of the drawings in detail and first,particularly to FIG. 1 thereof, there is shown a section of a fabricbelt 1 in an installation for producing a paper web, on which a layer ofa fibrous stock 2 is found and which is moved in the direction of arrowM over a group of drainage foils 3. The fibrous stock 2 is sprayed ontothe fabric belt 1 at the start of the latter. The drainage foils 3 areeach formed on their upper side with an overlay 4 made of awear-resistant material. Underneath the drainage foils 3 there is asuction box 5, in an interior 51 of which there is a vacuum of about −2mbar to −700 mbar. The drainage foils 3 are located on a supportingframe 52, which is detachably fixed to the upper side of the suction box5.

The fabric belt 1, which extends over a length of up to about 50 m andcan have a width of 2 m up to 12 m, is moved over the drainage foils 3at a speed of, for example, 1 m/s to 40 m/s by means of transport rollslocated in the installation.

The drainage foils 3 are usually but not necessarily produced fromacid-resistant stainless steel, from a plastic, e.g. from polyethylene,or from a glass fiber reinforced plastic. The suction box 5 is generallylikewise produced from acid-resistant stainless steel. The overlays 4found on the supporting bars 3 are preferably plates made of a ceramicmaterial, e.g. Al oxide (hardness HV 0.5 18,000 N/mm²), Zr oxide(hardness HV 0.5 12,700 N/mm²), Si nitride (hardness HV 0.5 18,800N/mm²), Si carbide (hardness HV 0.5 28,150 N/mm²).

As a result of the vacuum prevailing in the interior 51 of the suctionbox 5, a suction force is exerted on the fibrous stock 2, by whichliquid 6 contained in the latter is extracted. The liquid 6 escapingfrom the fibrous stock 2 passes through the fabric belt 1 and reachesthe underside of the fabric belt 1, from which, during the movement ofthe fabric belt 1 over the drainage foils 3, it is stripped off thelatter and reaches the suction box 5, through which it is led away.

FIG. 1A illustrates the drainage foil 3 having the wear-resistantoverlay 4 and the fabric belt 1 moved over the latter, on which thefibrous stock 2 is found. As can be seen herefrom, the fabric belt 1,which consists of a fabric, e.g. of polyamide or of polyester, has warpthreads 1 a oriented in the longitudinal direction of the fabric belt 1and weft threads 1 b oriented in the transverse direction of the fabricbelt 1.

During the movement of the fabric belt 1 over the drainage foils 3 inthe direction of the arrow M, during which the fabric belt 1 rests onthe surface of the overlays 4 of the drainage foils 3, high frictionalresistances occur, which have to be overcome by the transport rollsfound in the fabric belt installation in order to move the fabric belt1. In addition, in this case, high wear of the fabric belt 1 and of thedrainage foils 3 and of the overlays 4 is caused, which means that thefabric belt 1 and the drainage foils 3 have only short service lives.During the movement of the fabric belt 1 over the drainage foils 3, bowwaves 61 are formed in the liquid 6 that has escaped from the fabricbelt 1, in front of the weft threads 1 b resting on the drainage foils3.

According to the prior art, the drainage foils 3 can be formed on theirupper side, facing the fabric belt 1 in the operating position, with amultiplicity of ceramic plates, which have lengths of, for example, 12mm to 230 mm in the direction of the drainage foils and widths of, forexample, 12 mm to 100 mm transverse to the drainage foils, and alsoheights of, for example, 2 mm to 10 mm. The hardnesses of the ceramicplates are preferably HVO,5 12,700 N/mm² to HVO,5 28,150 N/mm². In orderto keep the frictional resistances which occur during the movement of afabric belt 2 over the drainage foils 3 as low as possible, the surfacesof the drainage foils 3, in particular the ceramic plates 4, areplane-ground according to the prior art, having surface roughness valuesRa of 0.15 μm to 0.7 μm.

FIG. 2 shows a drainage foil 3 according to the invention. The drainagefoil 3 differs from a drainage foil according to the prior art in thefact that the ceramic plates 41 found on its upper side are formed withelevations and/or depressions on their upper side facing the fabric belt1 in an installation for producing a paper web, wherein the heightdifference of the elevations with respect to the depressions is 0.1 mmto 1.6 mm. The elevations and depressions in embodiments of theinvention that are particularly preferred and described below in variousvariants have a profiling with a defined cross-sectional shape anddistribution over the surface of the ceramic plates 4. The dimensionsand the material of the ceramic plates 41 are preferably those accordingto the above-described known prior art.

FIG. 3 illustrates a first embodiment of the ceramic plate 41 found on adrainage foil 3 according to the invention, which is formed with aprofiling on its surface. The ceramic plate 41, which in the directionof movement M of the fabric belt 1 has a width B of, for example, 8 mmto 70 mm, preferably of 12 mm to 25 mm, and a height of, for example, 2mm to 10 mm, is provided on its surface with ribs 42 extending in thelongitudinal direction of the drainage foil 3, triangular orsaw-tooth-like in cross section and having upper edges 45, whereindepressions 43 are found in the regions of the flanks located betweenthe edges 45. The width B1 of a rib 42 is, for example, 1 mm to 16 mm,preferably 2 mm to 6 mm, and the height difference T between the edges45 of the ribs 42 and the bottom of the depressions 43 is at least 0.1mm, preferably up to 1.6 mm, particularly preferably 0.2 mm to 0.8 mm.The lateral regions 44 of the ceramic plate 41, which have a width A of,for example, 1 mm to 8 mm, preferably of 2 mm to 6 mm, are likewiseformed flatly. Thus, the surface of the ceramic plate 41 is formed witha defined profiling according to the invention, consisting of elevationsand depressions, wherein the ribs 42 that are saw-tooth-like in crosssection form the elevations with the edges 45, and the regions of theflanks of the saw-tooth-like ribs 42 located between the edges 45 formthe depressions 43.

The described formation of the surface of the drainage foils 3, inparticular of the surfaces of the ceramic plates 41, particularlypreferably but not necessarily with a defined profiled surface, is basedon the finding that, as a result of the relatively large elevations anddepressions formed according to the invention, the frictionalresistances occurring during the movement of the fabric belt 1 over thedrainage foils are reduced down to about 50%, which means firstly that asignificant reduction in the drive power for the fabric belt 1 can beachieved and secondly the service lives of the fabric belt 1 and of thedrainage foils 3 are substantially prolonged.

As can be seen from FIG. 3A, which corresponds to the illustration ofFIG. 1A, this action is achieved in that first the fabric belt 1 in theregions of the depressions 43 does not rest on the surface of thedrainage foil 3 or the surfaces of the ceramic plates 41, which meansthat no frictional resistances occur in these regions, and that, second,because of the movement of the fabric belt 1, bow waves 61 occur in theliquid 6 found in the depressions 43, by means of which the fabric belt1 in the regions of the elevations 42, in particular the edges 45, islifted over the latter, and by means of which liquid gets between theelevations and the fabric belt 1, by means of which the frictionalresistances between the elevations and the fabric belt 1 are reducedhighly.

FIG. 4 illustrates a further embodiment of the ceramic plate 41 aprofiled in a defined manner according to the invention and having awidth B, in which, between the lateral regions 44 a which form theelevations and which have a width A of, for example, 1 mm to 8 mm,preferably of 2 mm to 6 mm, there is a depression 43 a, the depth ofwhich with respect to the lateral regions 44 a is at least 0.1 mm topreferably 2.5 mm, particularly preferably 0.2 mm to 0.8 mm.

In the further embodiment, illustrated in FIG. 4A, of the ceramic plate41 b according to the invention having a width B, elevations in the formof ribs 42 b of rectangular cross section and depressions in the form ofrectangular grooves 43 b, which have widths B2 and B3 of, for example, 1mm to 10 mm, preferably 2 mm to 8 mm, are located between the lateralregions 44 b having a width A, wherein the height difference T2 betweenthe elevations formed by the ribs 42 b and the depressions formed by thegrooves 43 b is at least 0.1 mm to preferably 3.0 mm, particularlypreferably 0.2 mm to 0.8 mm.

In the further embodiment, illustrated in FIG. 4B, of the ceramic plate41 c according to the invention having a width B, there is a wave-likeprofiling with ribs 42 c and depressions 43 c that are concave in crosssection located in between two lateral regions 44 c having a width A,wherein the distance B4 between two depressions 43 c is, for example, 1mm to 20 mm, preferably 2 mm to 8 mm, and the height difference T3between the upper sides of the ribs 42 c and the bottoms of thedepressions 43 c is at least 0.1 mm to preferably 3.0 mm, particularlypreferably 0.2 mm to 0.8 mm.

The elevations 44 a, 42 b, 42 c and depressions 43 a, 43 b, 43 c of theembodiments of the invention illustrated in FIG. 4 to FIG. 4B areoriented in the longitudinal direction of the drainage foil 3 andpreferably extend over the entire length of the ceramic plates 41 a, 41b, 41 c.

In the further embodiment of a ceramic plate 41 d according to theinvention, illustrated in FIG. 5 and FIG. 5A, the defined profiling isformed by elevations in the form of rectangular ribs 42 d anddepressions located in between in the form of rectangular grooves 43 d,which have widths B5 and B6 of, for example, 1 mm to 10 mm, preferablyof about 2 mm to 8 mm, and a height difference T4 of at least 0.1 mm topreferably 3.0 mm, particularly preferably of 0.2 mm to 0.8 mm. Thelongitudinal extent of the ribs 42 d and the depressions 43 d found inbetween encloses an angle W1 of 0° to 80°, preferably of 30° to 55°,with the longitudinal extent of the drainage foil 3.

In the further embodiments of two ceramic plates 41 e, 41 f, accordingto the invention, illustrated in FIG. 6, FIG. 6A and FIG. 6B, the platesare formed with profilings in the form of concave cut-outs 43 e andcylindrical cut-outs 43 f located close beside one another on asubstantially flat surface, possibly somewhat curved as described below,which are spaced apart from one another. The distances B7 between thecenters of two cut-outs 43 e and 43 f located beside one another are, inthis case for example, 1 mm to 20 mm, preferably 2 mm to 12 mm, and thedepths T5 of the cut-outs are at least 0.1 mm to preferably 3.0 mm,particularly preferably 0.2 mm to 0.8 mm.

The cut-outs can also have another shape, both in plan view and also incross section, in particular an elongate or elliptical shape.

The ceramic plate 41 g according to the invention illustrated in FIG. 7corresponds to the embodiment according to FIG. 3, having ribs 42 g thatare saw-tooth-like in cross section and having edges 45 g which form theelevations, and depressions 43 g in the regions of the flanks of thesaw-tooth-like ribs 42 g, wherein the lateral regions 44 g having awidth F of, for example, 1 mm to 20 mm, preferably of 2 mm to 8 mm, areformed so as to fall obliquely toward the outside with an angle of, forexample, 2° to 10°, preferably of 3° to 6°, and, in addition, the outeredges are rounded with a radius R of, for example, 0.5 mm to 5 mm,preferably of 1 mm to 3 mm.

A further embodiment of a drainage foil according to the invention isnow explained. According to the known prior art, the surfaces ofdrainage foils are formed flat and the surfaces of drainage foils foundon suction boxes are located in a common plane. However, as a result ofthe fact that a suction action is exerted by the suction boxes on thefabric belt in the interspaces found between the drainage foils, thefabric belt is drawn into the interspaces found between the drainagefoils. In this way, the two lateral regions of the surfaces of thedrainage foils, in particular of the overlays of a wear-resistantmaterial found on the latter, for example ceramic plates, are loadedmore highly than is the case for the central regions of the surfaces ofthe drainage foils, located in between.

In order to achieve a uniform pressure distribution over the width ofthe drainage foils 3 a, as can be seen from FIG. 8 and FIG. 8A, thesurfaces of the ceramic plates 4 a found on the drainage foils 3 a havea curvature or are formed convexly in cross section, which means thatthe fabric belt 1 overall assumes a wave-like course. The drainage foils3 a are located on a supporting frame 52 a, which is detachably fixed tothe suction box 5.

As can also be seen from FIG. 8A, the radius R1 of the curved surfacesof convex cross section of the ceramic plates 4 a located on thedrainage foils 3 a is, for example, 100 mm to 500 mm, preferably 200 mmto 350 mm. In addition, the side edges of the drainage foils 3 a arerounded, the radius R2 of the rounding of the side edges being, forexample, 0.5 mm to 5 mm, preferably 1 mm to 3 mm.

By means of such a formation of the surfaces of the drainage foils 3 a,in particular of ceramic plates 4 a found on the latter, a uniformdistribution of the pressure exerted by the fabric belt 1 over the widthof the drainage foils 3 a is effected, which likewise means firstly thatthe frictional resistances and secondly the wear of the fabric belt 1and of the drainage foils 3 a are reduced.

This further formation of the drainage foils 3 a is in particularcombined with the profiling of the surface of the drainage foils, whichcan be provided with a wear-resistant overlay 4 a, e.g. with ceramicplates, as is explained above by using FIG. 2 to FIG. 7.

The formation of drainage foils according to the invention is inparticular advantageous in those drainage foils which are located on asuction box.

The drainage foils can be provided with overlays of ceramic plates.However, the drainage foils can also be produced overall frompolyethylene, not being coated with ceramic plates. In addition, thesurfaces, in this case, are formed with a profiling in the form ofelevations and/or depressions with a vertical extent of at least 0.1 mmto preferably 3.0 mm.

As soon as the elevations have been ground off by the use of thedrainage foils, the surfaces are re-machined to the effect that theheight differences between the elevations and depressions required forthe specified action are reproduced.

All the embodiments described in conjunction with overlays of awear-resistant material, in particular ceramic, can also be used withinthe context of the invention in drainage foils which have overlays ofanother material, in particular materials not having such good wearproperties, and likewise in drainage foils which have no overlays, inwhich the elevations and depressions are applied to or formed directlyon the drainage foils.

All the embodiments illustrated and described can be combined wholly orpartly with one another and with embodiments which have not actuallybeen illustrated and described.

1. A drainage foil for use in an installation for producing a paper webwith a fabric belt, the fabric belt being moved over a multiplicity ofdrainage foils oriented transversely to a direction of movement, thedrainage foil comprising: a drainage foil body having a surface formedwith a defined profiling, said defined profiling having elevationsand/or depressions, and a vertical extent of said defined profiling isat least 0.1 mm.
 2. The drainage foil according to claim 1, wherein saidelevations and said depressions define said defined profiling and/or aredistributed in a defined manner over said surface.
 3. The drainage foilaccording to claim 1, wherein said drainage foil body has ceramic platesdisposed beside one another and defining said surface of said drainagefoil body, said elevations and/or said depressions are formed on asurface of said ceramic plates, wherein the vertical extent of saiddefined profiling is at least 0.1 mm.
 4. The drainage foil according toclaim 1, wherein the vertical extent of the defined profiling is up to3.0 mm.
 5. The drainage foil according to claim 1, wherein said surfaceis formed with said defined profiling oriented in a longitudinal extentof said drainage foil body or enclosing an acute angle with saiddrainage foil body in a form of ribs that are triangular in crosssection.
 6. The drainage foil according to claim 1, wherein said surfaceis formed with said defined profiling oriented in a longitudinal extentof said drainage foil body or enclosing an acute angle with saiddrainage foil body in a form of bars that are rectangular in crosssection and rectangular grooves.
 7. The drainage foil according to claim1, wherein said surface is formed with said defined profiling orientedin a longitudinal extent of said drainage foil body or enclosing anacute angle with said drainage foil body in a form of bars that arewave-shaped in cross section.
 8. The drainage foil according to claim 3,wherein said defined profiling of said ceramic plates disposed besideone another are offset with respect to one another transversely to alongitudinal direction of said drainage foil body.
 9. The drainage foilaccording to claim 6, wherein a longitudinal extent of said elevationsand/or said depressions enclose an angle of 0° to 80° with alongitudinal extent of said drainage foil body.
 10. The drainage foilaccording to claim 1, wherein said defined profiling is formed bycut-outs formed in said surface and are concave in cross section and aredisposed at a distance from one another or by cylindrical holes.
 11. Thedrainage foil according to claim 1, wherein said surface has a convexcurvature in a section transverse to a longitudinal extent of saiddrainage foil body.
 12. The drainage foil according to claim 11, whereinsaid convex curvature has a radius of 100 mm to 500 mm.
 13. The drainagefoil according to claim 1, wherein said surface has side edges that arerounded in cross section with a radius of 0.5 mm to 5 mm.
 14. Thedrainage foil according to claim 1, wherein the vertical extent of theprofiling is up to 1.6 mm.
 15. The drainage foil according to claim 1,wherein the vertical extent of the profiling is between 0.2 mm and 0.8mm.
 16. The drainage foil according to claim 6, wherein a longitudinalextent of said elevations and/or said depressions enclose an angle of30° to 55° with the longitudinal extent of said drainage foil body. 17.The drainage foil according to claim 11, wherein said convex curvaturehas a radius of 200 mm to 350 mm.
 18. The drainage foil according toclaim 1, wherein said surface has side edges that are rounded in crosssection with a radius of 1 mm to 3 mm.
 19. A kit for an installation forproducing a paper web, comprising: a supporting frame configured to bedetachable fixed on a suction box of the installation; and drainagefoils disposed on said supporting frame, said drainage foils eachcontaining a drainage foil body having a surface formed with a definedprofiling, said defined profiling having elevations and/or depressions,and a vertical extent of said defined profiling is at least 0.1 mm. 20.An installation for producing a paper web, comprising: a plurality ofdrainage foils each containing a drainage foil body having a surfaceformed with a defined profiling, said defined profiling havingelevations and/or depressions, and a vertical extent of said definedprofiling is at least 0.1 mm; and a fabric belt being moved over saidplurality of drainage foils extending transversely to a direction ofmovement.